Synthesis of Catalytic Porous Metallic Nanorods by Galvanic Exchange Reaction

We demonstrate a simple method for the synthesis of nanoporous metal (Au, Pt, and Pd) rods by the galvanic exchange reaction using Ni as a sacrificial template. Nickel nanorods, prepared by electrodeposition inside porous alumina membrane, were converted to various nanoporous metallic structures by dispersing them in metal salt solutions of the respective metals that are galvanically exchanged. The catalytic activity of the porous Pt and Pd nanorods in the hydrogenation of ethylene was comparable to supported Pt and Pd nanoparticles. The porous nanorods provide a new form of unsupported catalysts in contrast to traditional supported nanoparticle catalysts and can be synthesized in uniform sizes and separated easily from the reaction mixtures without aggregation.